At present, antiaging agents used for a rubber, thiazole vulcanization accelerators and sulfenamide vulcanization accelerators are synthesized from aniline which is produced from petroleum as a raw material. Assuming a rise in oil prices and exhaustion of oil, a production process which does not use oil is desired. Further, processes of production of antiaging agents and vulcanization accelerators cause global warming since industrial production of aniline from petroleum resources emit a large amount of heat and carbon dioxide. Therefore, based on an idea of utilizing natural resources, a method is known wherein a vulcanization accelerator is synthesized by the use of a naturally-derived long-chain amine, as a material, which is obtained by reductive amination of a saturated or unsaturated fatty acid which is obtained by hydrolysis of a natural fat and oil (JP-A-2005-139239).
However, acrylonitrile, mercaptobenzothiazoles and dibenzothiazolyl disulfide are used in the process of producing vulcanization accelerators. There is no description that these materials are produced from natural resources.
Further, a production process is known wherein a modified natural rubber is produced by a graft polymerization or an addition of a compound containing a polar group under mechanical shear stress to a natural rubber raw material (JP-A-2006-152171). However, it is not assumed that a naturally-derived material is used as a compound containing a polar group.